JPS6354591B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid operated vehicle steering system of the type having a rotary regulator.

GB 985230 discloses a steering control member extended by a regulator sleeve, a generally tubular rotor disposed within the regulator sleeve, and a generally tubular rotor disposed within the rotor and secured at one end to the rotor. a torsion bar having an end secured to the steering control member;
A fluid-actuated vehicle steering system is described having a fluid circuit that generates a control value corresponding to an angular displacement imposed on a rotor.

The invention is primarily aimed at a device of the above-mentioned type, in which the application of the fluid circuit to given small changes in the control value does not pose any difficulties, and in which the components of the fluid circuit can be easily manufactured. .

In fact, another problem with such devices is that, at high speeds, flow noises due to cavitation conditions are observed. Intermittent noise audible to the user is unpleasant and the present invention aims to substantially reduce flow noise to a large extent.

Accordingly, the present invention provides a steering control member extended within a housing by a regulator sleeve, a generally tubular rotor disposed for rotation within the regulator sleeve, and a generally tubular rotor disposed within the rotor having one end connected to the rotor. a torsion rod fixed to the steering control member at its other end, a fluid circuit for producing a controlled variable corresponding to the angular displacement imposed on the rotor, the rotor having at least two sets of parallel longitudinal grooves; each set of grooves communicates at least with a fluid circuit portion forming a working chamber or fluid pressure source or reservoir of an auxiliary fluid motor via a generally radially extending passageway formed in the sleeve; A fluid-operated steering system for a vehicle in which at least two sets of diametrically opposed apertures are formed facing a peripheral land of a rotor between two adjacent said grooves belonging to two different said sets, said apertures comprising: The ports include holes formed generally radially in the wall of the sleeve and arranged in two axially offset sets opening respectively into two annular chambers formed between the sleeve and the housing; The chambers are in fluid communication with the other portions of the set of fluid circuit portions, the cavity between the torsion rod and the rotor is connected to the reservoir, and the cavity is connected to the groove for fluidly connecting one of the set of grooves with the cavity. A regulator device is provided in each groove in fluid communication with the groove, the regulator device is provided to generate a back pressure in the groove in the event of angular movement of the rotor, and the regulator device is provided in fluid communication with the groove. a first set of passages symmetrically formed in the rotor to connect the cavity around the circumference of the rotor; and a first set of passages each formed in the sleeve symmetrically with respect to the groove of the rotor in a neutral position. and a second set of passages communicating with the groove.

The passages in the sleeve have a special orifice shape as described below, allowing the passages in the rotor to be axial grooves. According to a preferred embodiment of the invention, the high pressure source and the exhaust passage are respectively connected to a pair of grooves in the rotor.

Also, in the preferred embodiment, the edges of the apertures are truncated wedge-shaped.

In a preferred embodiment, which makes it possible to greatly reduce the flow noise due to the cavitation phenomenon, the cavity formed between the torsion rod and the rotor communicates with the discharge channel and connects one of the sets of grooves to the cavity. For this reason, passages are provided in each case such that an angular displacement of the rotor creates a back pressure in the groove.

The generation of back pressure in the grooves connected to the discharge channels during steering leads to a considerable reduction in cavitation in these grooves and thus in a considerable reduction in the flow noise.

The invention will be more easily understood from the following detailed description taken in conjunction with the accompanying drawings.

Referring to FIG. 1, steering control member 110
In the example described, it is constituted by a pinion of the rack and pinion steering type, and the reference numeral 112 designates the rotary regulator of the fluid-actuated steering device.

Rotary regulator 112 has a casing 114 in which a hole 116 is formed. This casing 114
is connected by a pin 115 to a base 117 secured to a rack casing (not shown). Also provided within the bore 116 of the casing 114 is a pinion or sleeve 120 which is an extension of the steering control member 110. This extension 120 is provided with a hole 122 coaxial with the hole 116, and the extension 120 forms a regulator sleeve.

A rotor 126 is rotatably provided within the hole 122, and the rotor 126 has a through hole 1.
27 are provided. The torsion rod 1 is inserted into the hole 127.
34, and the outer end of this torsion rod 134, that is, the right end in FIG. 1, is fixed to the rotor 126 by a pin 136. Torsion rod 134
The inner end, that is, the left end in FIG.
It is fixed to the pinion 110 by a pin 138 within a hole 122 provided in the hole 122 provided in the pinion 110 . rotor 126
is therefore elastically connected to pinion 110.

The pin 138 extends laterally with a gap 140 within a groove 142 formed in the end of the rotor 126 so that the pinion 110 rotates with the rotor 126 over an angular displacement and is inserted into the fluid circuit. It is designed to be able to deal with possible failures.

This configuration consists of a pinion 110 and a torsion rod 13.
4, the torsion rod 134 is held by the pinion 110 and by the rotor 126.

Furthermore, in the illustrated embodiment, the bearing 132 is connected to the pinion 110, which is a steering control member, and the casing 11.
4 and together rotatably support a rotor 126 rotatably provided in a hole 122 of an extension 120 of the pinion 110.
Further, if necessary, a suitable bearing such as a needle bearing can be provided between the casing 114 and the rotor 126. However, such bearings are not always indispensable, and pinion 1
It should be noted that if 10 and sleeve 120 are integrally constructed such that sleeve 120 acts as a bearing for rotor 126, such a bearing may be omitted.

In addition, the casing 114 has a high-pressure hole 144 on one side and a low-pressure hole 146 that is connected to a metering pump, tank, etc. during operation.
On the other hand, two orifices, only one of which is designated by the numeral 148 in the drawing, are connected in operation to respective chambers V1, V2 of a power auxiliary jack (not shown), forming passages or passages formed in the sleeve 120. It communicates with annular chambers 154 and 158.

The extension or sleeve 120 has four annular chambers 154 , 156 , 158 , 160 , the tightness between each annular chamber being greater than that of the body or casing 114 .
This is achieved through extremely precise machining of the bearings that come into contact with the bearings.

The annular chamber 154 is connected to the power auxiliary jack chamber V2 through a hole 148 formed in the casing 114.
connected to one of the Annular chamber 156 is connected to a high pressure fluid pressure source HP, such as a metering pump, through port 144 (FIG. 4). Annular chamber 158
is a hole (third hole) in another chamber V1 of the power auxiliary jack
(Figure). Further, the annular chamber 160 is connected to the tank BP via a low pressure port 146.

The sleeve 120 also has two diametrically opposed openings 161 with a rectangular cross section, as shown in FIG. 5, at the position of the annular chamber 154 connected to the chamber V2;
Two holes 163 of the same shape are offset by 90 degrees from the hole 161 at the position of the annular chamber 158 connected to the chamber V1.
It has

On the one hand, the rotor 126 has four long grooves 165, 167 provided at equal angular intervals on its outer periphery, as shown in FIGS. 3-5.

The edge 169 of the aperture 161, oriented along the axis of the sleeve 120, has a non-linear shape as shown in FIG. That is, FIG. 6 is a view of the edge 169 of the sleeve 120 viewed from the outside toward the center in the radial direction, showing a protrusion 180 and two grooved portions 181 parallel to the axis of the sleeve 120.
It has a wedge shape in which a portion 182 inclined with respect to the axis is connected. It is clear that by changing the shape features, one factor in the angular displacement between the rotor 126 and the sleeve 120 is changed in such a way that the cross-section of the passage and thus the valving characteristics of the device are changed. . Also, hole 1
The edges 171 of 63 represent the same shape.

Groove 167 is permanently connected to a high pressure source via a radial passageway 173 made in sleeve 120.

Groove 165 is permanently connected to tank BP as follows. For each groove 165, two radial passages 175 are provided in the sleeve 120 symmetrically to the groove 165, assuming a neutral position of the regulator device. These passages 17
5 are communicated with each other through a groove 165.

Two further passages 177 are provided in rotor 126 on either side of groove 165 to communicate with passage 175, respectively. These passages 177 are connected to the rotor 126
and the torsion rod 134 . The channels through which the fluid flows are indicated by arrows in FIG. Furthermore, cavity 179 communicates with annular chamber 160 by means of aperture 183 .

A regulator configured in this manner operates as follows.

In the rest position shown in FIG. 1, when a steering torque is applied, for example to the right, the rotor 126
This causes the sleeve 120 to rotate clockwise (FIGS. 2-5), but the sleeve 120 does not rotate due to the elasticity of the torsion rod 134.

This relative displacement between sleeve 120 and rotor 126 increases the passage cross-sectional area between groove 167 and aperture 163 (FIG. 3), causing
(Fig. 5) has the effect of reducing the passage cross-sectional area.

This effect is opposite for the passage cross-sectional area between the grooves 165 on the one hand and the passage cross-sectional area between the holes 161 and 163 on the other hand.

This is so that when the groove 167 is connected to the high pressure source HP, the pressure in the port 163 communicating with the chamber V1 increases and the pressure in the port 161 communicating with the chamber V2 decreases. The difference in pressure between chambers V1 and V2 determines the force exerted by the auxiliary jack.

This difference in the pressure established between chambers V1 and V2 is a factor in the steering torque applied and, as explained, in the shape chosen at edges 169, 171.

In the case of steering to the left, the opposite occurs, ie the pressure in chamber V1 decreases and the pressure in chamber V2 increases, resulting in a movement of the movable member of the jack in the opposite direction.

In this manner, the regulator arrangement consisting of the set of passages 175, 177 connecting groove 165 to tank BP acts to create a back pressure within groove 165 to reduce cavitation phenomena. In fact, this regulator device acts like a fluid Whitstone bridge,
The angular displacement of the rotor 126 during steering action is caused by the groove 1
The pressure inside 65 is increased.

Flow noise at a pressure in the jack chamber of 5 to 7 bar, which corresponds to the small steering angles of normal operation of the vehicle, is thus almost eliminated. The noise is only audible when considerable steering action is carried out and the pressure is
Reaching 30 bar.

It may be emphasized that the components of the fluid circuit described above are simpler to manufacture than those of prior art devices. In particular, the grooves 165, 167 of the rotor 126 can be milled to normal tolerances, and the holes 161, 163 formed in the sleeve 120 can be obtained by broaching or milling in the blind area, and the holes 161, 163 formed in the sleeve 120 can be obtained by broaching or milling in the blind area. Finishing performed by drilling or boring can be done later.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a fluid-operated vehicle steering system according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line - in FIG. 1, and FIG. 4 is a sectional view taken along line - of Fig. 1, and Fig. 5 is a sectional view taken along - line of Fig. 1.
A cross-sectional view along a line, FIG. 6, is an enlarged detail of the edge of the hole. In the figure, 110: pinion, 112:
Rotation regulator, 114: Housing, 115, 13
6,138: pin, 116,120: hole, 12
0: Sleeve, 126: Roller, 134: Torsion rod, 142, 165, 167: Groove, 146, 14
8,161,163,183: Kongou, 154,1
56, 158, 160: annular chamber, 169, 17
1: Edge, 173, 175, 177: Passage, 17
9: Blank space, 180: Protruding part, 181: Grooved part, 1
82: Inclined part, BP: Tank, HP: Fluid pressure source, V1, V2: Chamber.

Claims (1)

[Claims] 1. Regulator sleeve 12 within housing 114
a generally tubular shaped rotor 126 disposed within the rotor for rotation within the regulator sleeve and secured to the rotor at one end and secured to the steering control member at the other end; a torsion rod 134 with a fluid circuit for producing a controlled variable corresponding to the angular displacement imposed on the rotor, the rotor 126 having at least two sets of parallel longitudinal grooves 165, 167 with each set of grooves a generally radially extending passageway 175 formed in the sleeve with a fluid circuit portion forming the working chamber or fluid pressure source HP or reservoir BP of the auxiliary fluid motor;
the sleeve has at least two sets of diametrically opposed apertures 161, 163 pointing toward a peripheral land of the rotor between two adjacent grooves belonging to two different sets. In the constructed vehicle fluid-operated steering system, the apertures 161, 163 open respectively into two annular chambers 154, 158 formed generally radially in the wall of the sleeve and formed between the sleeve and the housing. apertures arranged in two axially offset sets, the annular chambers being in fluid communication with the other parts of the set of fluid circuit parts, respectively, and a cavity 1 between the torsion rod and the rotor;
79 is connected to the pool BP, grooves 165, 167
regulator devices 175, 177 for fluidly connecting the groove and the cavity to fluidly connect one of the sets of the grooves to the cavity 179;
is provided in each groove, the regulator device is provided to generate a back pressure in the groove in case of angular movement of the rotor, and the regulator device is formed in the rotor symmetrically with respect to the groove. a first set of passages 177 connecting the cavities around the rotor; and a second set of passages 177 formed in the sleeve symmetrically with respect to the grooves of the rotor in the neutral position and communicating each of the first set of passages with the grooves. A fluid-operated steering system for a vehicle, characterized in that it has a set of passages 175. 2 It has two sets of grooves and two sets of holes, and the holes are
A fluid-operated steering system for a vehicle according to claim 1, characterized in that the steering system is 90° angularly offset. 3. The fluid-operated steering device according to claim 1, wherein the edge of the aperture is wedge-shaped. 4. The fluid-operated steering device according to claim 3, wherein the protruding portion of the hole is connected to the grooved portion by an inclined portion. 5. The connection between said steering control member and the end of the torsion bar is made by means of a diametrical pin passing through a groove formed in the rotor with a clearance, so that if necessary there is a connection between the rotor and the steering control member. 5. A fluid-operated steering device according to any one of claims 1 to 4, wherein the mechanical connection of the steering wheel is ensured by a pin.